A single-component developer has usually been used for forming a color image in an electrophotographic method. As the image forming method using a single-component developer, a procedure is known in which a latent image formed on an electrostatic latent image carrying member is developed by the single-component developer composing a toner which is conveyed and supplied by a developer carrying member, and then thus obtained toner image is transferred onto an image receiving material, and the toner constituting the transferred toner image is fixed by heating.
In such a method, the necessary amount of static charge is given to the toner by triboelectricity since the toner is adhered to the developer carrying member by static charge and is conveyed. As a result, a problem resulted such that the toner is molten by the frictional effect and adhered as contamination to the constituents of the image forming apparatus, such as the developer carrying member.
Accordingly, a high quality image cannot be obtained since problems such as formation of unevenness of the image occurs even when a sufficiently high fixing performance of the toner is displayed.
In addition, when the toner contains an external additive, high transferring performance and developing performance are obtained with difficulty since such developer accompanies various problems caused by releasing of the external additive from the toner particle, or burying of the external additive into the toner particle.